In a new video game for cell phones set to launch in Japan, the point is simple: Roaming players must point their handsets in the right direction to score.

Clicking on the real world with a mobile could open up cities for residents and tourists and opportunities for advertising.

Called Navimon, the game requires a cell phone that sports both GPS and an internal compass. Comfy shoes help, too.

It works like this: Players get a random alert indicating that (quick!) space monsters are now hovering around the Tokyo Tower or any 7-Eleven outlet, for instance. The cute, cartoonish aliens are lost, and they need help getting home.

The objective is to find them then assist them back to their planet. To find an alien, players point their phones at, say, a 7-Eleven outlet. If their aim is true, the alien appears on the game page (whining that it's thirsty, perhaps) and players click a button to send it home.

Players get points each time they help aliens, some of which are worth more than others because they're hard to find or have special abilities. A "high scores" page in Navimon lists the best players around, and another page inventories every alien helped.

The bad news: Navimon probably won't be coming to a sidewalk near you anytime soon. Though it will expand, this month the game is scheduled to launch in just three cities (Tokyo, Osaka, and Nagoya), is offered only in Japanese, and is available through just one carrier, KDDI.

Players outside mobile-savvy Japan will have to wait.

Of course using GPS data to link virtual worlds to the real world (or vice versa) is not new in mobile gaming -- witness virtual treasure hunts on city streets and the like. GPS plus pointing, though, suggests an entirely new direction.

Even in Japan, GPS compass phones are still relatively rare. That's partly because a compass adds a bit to manufacturing costs while its benefits have not always been made clear.

Quality varies, too, with some compass phones prone to falling out of calibration -- not good for a game like Navimon. But as compass phones improve and spread, new possibilities will open up.

In upcoming Navimon versions, the aliens will appear not on a game page, but through the viewfinder, superimposed over the real world. So if you look at a 7-Eleven outlet, you might see a tiny yellow alien hovering by the door, visible only through the viewfinder and invisible to others.

Next-gen "6D" compass phones with accelerometers detect six dimensions: flat, up, down, roll, pitch and altitude. So the aliens could fly around instead of just hover. Picture a space monster the size of a blimp drifting around the Tokyo Tower, visible only to Navimon players.

Pointing to profit with highly focused advertising

Navimon was created by GeoVector a technology design firm based in San Francisco whose logo is "click on the real world."

GeoVector and its partners have a vested interest in people pointing their cell phones.

They aim to profit from sponsored virtual information superimposed on the real world -- augmented reality -- and accessed primarily via cell phones.

This helps explain why they started off in Japan, with its advanced mobile market.

The idea: Suppose a city monument has caught your interest. To learn what it's called, you could just point your phone at it. In the viewfinder, the monument's name would pop up next to it. Other objects might be labeled too, with more info available through links.

So far, it's an advertising-free experience -- the "white pages" of augmented reality.

For GeoVector and its partners, the money is in the "yellow pages," which you access with an opt-in click. Most objects in the real world could potentially be overlaid with sponsored virtual information.

In the monument's case, perhaps you'd learn that a book about its history is available at a nearby shop, or at Amazon.com. Or you could point to a movie theater and get trailers of what's playing.

Some of these location-based services are already happening.

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For a few years now users in Japan have been tapping services like Mapion (in which GeoVector is a partner), which lets them point their phones in any direction to see what restaurants, hotels, or ATMs -- or promotions -- are up ahead, and then follow an on-screen swiveling arrow to find them.

As GPS precision is enhanced with various technologies, users are able to point at ever smaller objects to retrieve information.

Mapion users can now point at a large building, for instance, to see what restaurant are inside, and then drill down to their menus.

For advertisers, the appeal is highly focused advertising. The audience is present, pointing, and requesting, after all, and so likely in a state of heightened interest at that very moment. The slightest nudge could lead to a purchase.

There are other encouraging signs for the proponents of point.

Google's new Android platform for cell phones has compass support. The first Android phone, the T-Mobile G1, has a compass and accelerometer combo.

Imagine seeing Google Street View when you're on the actual street, and having it adjust to your movements when you turn around.

Responses to Navimon during its test phase have been promising, says GeoVector president John Ellenby.

"It's turning out to be a very compelling game because people do want to help these monsters get home," he says.

Of course anything involving cute creatures and cell phones has a shot in Japan. In fact GeoVector is taking no chances: In the unlikely event the game goes Hello Kitty, it's trademarked the alien characters. (Navimon figurines, anyone?)

But that's a long shot given the game's limited audience, especially early on.

And for most people, the ideas of augmented reality and handset-pointing are well off the radar. (Sympathy goes to salespeople explaining virtual hovering space aliens to potential Navimon sponsors.)

For GeoVector, it's enough if the game gets some more people pointing their cell phones. "People are very curious about their environment," says Ellenby, "whether there are fictitious monsters there or not."